Sly syndrome is an autosomal recessive lysosomal storage disease caused by a deficiency of the enzyme β-glucuronidase.
This enzyme is responsible for breaking down large sugar molecules called glycosaminoglycans.
Sly syndrome is also called mucopolysaccharidosis type VII and is a progressive condition that affects most organs and tissues.
Some people with Sly syndrome may begin to have symptoms in early childhood.
Symptoms of sly syndrome can include an enlarged head, fluid buildup in the brain, coarse facial features, enlarged tongue, enlarged liver, enlarged spleen, problems with the heart valves, and abdominal hernias.
Fetal deaths in sly syndrome have been reported in severe cases.
In people with milder cases of sly syndrome, survival to age 19-20 years has been reported.
Upper respiratory tract infections, neurodegenerative complications, and gastrointestinal conditions contribute to a reduced life expectancy in sly syndrome.
Mucopolysaccharidosis type VII (MPS VII) is an ultra-rare, life-threatening, progressive disease caused by genetic mutations that affect lysosomal storage/function.
MPS VII has an estimated prevalence of <1:1,000,000 and accounts for <3% of all MPS diagnoses.